1. Field
Apparatuses and methods consistent with the exemplary embodiments relate to a reflection-type electrochromic device that easily switches between transparent and reflective states.
2. Description of Related Art
A reflection-type electrochromic device (ECD) may switch between a light transmission mode and a light reflection mode according to applied voltage.
The reflection-type electrochromic device generally includes a laminate structure composed of substrates serving as a transparent substrate, a transparent electrode, an ion storage layer, an electrolyte layer, a catalyst layer, and an active layer.
The ion storage layer comprises transition metal oxide and protons stored in the ion storage layer are moved to the active layer upon application of voltage.
The active layer changes optical properties from a reflective state to a transmissive state upon movement of protons. Meanwhile, upon application of a reversely-charged voltage, the protons are moved back to the original position, i.e., the ion storage layer, and the optical property of the active layer is changed to the reflective state again. Such a reversible oxidation-reduction (redox) reaction causes change in optical property to transmission mode or reflection mode.
Furthermore, the electrolyte layer is disposed between the ion storage layer and the active layer and facilitates movement of ions. The catalyst layer is generally disposed between the active layer and the electrolyte layer and facilitates the oxidation-reduction reaction of the active layer.
In related art, the catalyst layer is generally at the interface of the active layer, but an electrochromic device having this structure has a problem of low light transmittance in a transmission mode because an oxidation-reduction reaction rate opposite to the interface between the active layer and the catalyst layer is lower than an oxidation-reduction reaction rate on the interface between the active layer and the catalyst layer and a catalyst layer composed of a metal is formed in the form of a layer.